CN100391570C

CN100391570C - A multi-effect distilling method for desalt and condensation and device

Info

Publication number: CN100391570C
Application number: CNB2006100790301A
Authority: CN
Inventors: 周堃
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-04-30
Filing date: 2006-04-30
Publication date: 2008-06-04
Anticipated expiration: 2026-04-30
Also published as: CN1864783A

Abstract

The present invention discloses a multi-effect evaporating concentration desalting method and a device adopting the method. The method mainly comprises a preheating step, an evaporating step, a condensing step, etc. and takes heating steam (or hot water) as the heat source to carry out concentration desalination. Corresponding devices comprise multi-effect evaporators which are connected with each other, and each multi-effect evaporator is composed of one set or a plurality of sets of plate type evaporating units concentrated solution in an evaporation basin of each evaporating unit is connected with the next-effect evaporating unit of the same set by a pipeline, or the concentrated solution of the sets of evaporating units of all the multi-effect evaporators. The present invention which has the advantages that the evaporating units are modularized, the heat transfer efficiency is high, and the scale formation is not easy is suitable for the dual purpose of desalination and condensation.

Description

A kind of multi-effect distilling method for desalt and condensation and device

Technical field

The present invention relates to a kind of multi-effect distilling method for desalt and condensation and the employed device of this method, particularly a kind of employing is the preheating solution to be concentrated step by step, organizes the plate evaporation unit module more, and plate-type evaporator adopts plate edge air inlet, advances the method and apparatus of concentrate.Can be widely used in that desalinization concentrates, saline sewage desalination concentration.

Background technology

At present, the method and apparatus that existing in the world multiple-effect evaporation concentrates adopts mostly and rises film or falling liquid film method and tubular type vaporising device.Its shortcoming is:

1. tubular evaparator manufacturing process complexity, manufacturing cost is higher; The tube wall surface fouling, the cleaning difficulty.

2. no matter be Natural Circulation or forced circulation in the climbing-film evaporation, because the tubular evaparator structure is limit, liquid level is higher, and consequent liquid level pressure makes the concentrate boiling temperature raise, and has reduced heat transfer temperature difference between each effect, reduces heat exchange efficiency.

3. in the falling film evaporation, concentrate forms film at tube wall surface, and when concentrate concentration was higher, tube wall surface very easily formed crystallization or fouling, influences heat exchange.

Present plate-type evaporator is owing to adopt the plate planar ends to establish air inlet, inlet.Steam inlet and concentrate inlet-duct area are very little, and flow is limited, can only be used for single effect evaporation, and concentrated solution discharge is little simultaneously, flow velocity is low, easy fouling.

Summary of the invention

The object of the present invention is to provide a kind of multi-effect distilling method for desalt and condensation and device, to solve manufacturing, maintenance, the maintenance complexity that prior art exists, manufacture difficulty is big, cost is high, and the low problem of heat transfer efficiency.

The present invention is achieved in that

A kind of multi-effect distilling method for desalt and condensation comprises preheating, evaporation, condensing steps in each is imitated, wherein:

Concentrated liquid to be evaporated in the described preheating step is preheated to first by the most last effect (temperature poor efficiency) step by step by multistage dense water, fresh water preheater and imitates (temperature is the most efficient).

Concentrated liquid to be evaporated in the described evaporation step is concentrated by stepped evaporation until the most last effect in first effect, second effect after the preheating successively, and the concentrate of finishing is extracted out from the most last effect; Every effect condensed water is imitated to enter step by step from first and is extracted out from the most last effect as desalination water after next effect is compiled.

The heat of first single-effect evaporator is supplied with by the external world in the described evaporation step, and second imitates the heat that reaches following each effect is provided by the indirect steam that last 1st effective evaporator evaporates.

The employed device of a kind of described multiple-effect evaporation method for concentration comprises interconnective multi-effect evaporator, and it is characterized in that: every single-effect evaporator is made up of one or more groups plate evaporation unit.Concentrate in the evaporation tank of every group of evaporation element, imitating on the same group by pipeline and next, evaporation element links to each other; After the concentrate that also every effect how can be organized evaporation element compiles, deliver to next effect.

Described plate evaporation unit is immersed in the evaporation tank by one or more plate-type evaporators and forms.

Described plate-type evaporator, its steam inlet and concentrate import are located at the edge side of plate.

The present invention possesses following characteristics:

1. method flow is reasonable, the apparatus structure modularization.Available identical evaporation element module combinations becomes the multiple-effect of different output scale to concentrate desalting plant, design, make, maintenance is simpler, has interchangeability, be fit to large-scale production, thereby reduce manufacturing cost.

2. alleviate equipment corrosion.Because high concentration is imitated at low temperature, low concentration is imitated at high temperature, therefore the corrosion that has alleviated equipment.

3. because plate type heat exchanger adopts the admission of plate edge side, feed liquor, increased area of passage and flow, the steam pressure that reduces to cause because of steam resistance loses, simultaneously, alleviated crystallization, the fouling of concentrate on plate, making the plate-type heat-exchange mode use in multiple-effect evaporation becomes possibility.

4. heat transfer efficiency height.Because adopt plate-type evaporator to improve heat transfer coefficient, heat transfer efficiency greatly improves than tubular evaparator.

Description of drawings

Fig. 1 is the overall formation schematic diagram of apparatus of the present invention;

Fig. 2 is the formation schematic diagram of evaporation element of the present invention;

Fig. 3 is the formation schematic diagram of plate-type evaporator of the present invention.

The specific embodiment

Referring to Fig. 1, device of the present invention is to be a separate unit with every effect; Steam between every effect, concentrate and fresh water are connected with pipeline.

Every effect is made up of single or multiple evaporation element A (every effect shown in this figure is three evaporation elements); Every effect all is furnished with independent dense water preheater D and fresh water preheater E, is used for preheating solution to be concentrated step by step.

Referring to Fig. 1 and Fig. 2, each evaporation element A is made up of single or multiple plate-type evaporator B (every evaporation element shown in this figure is three plate-type evaporators), and is immersed among the evaporation tank C.

In above-mentioned device, dense water preheater D and fresh water preheater E finish the concentrate preheating step in the inventive method, evaporation and concentration and condensing steps in plate-type evaporator B and the evaporation tank C Method Of Accomplishment.

Referring to Fig. 3, plate-type evaporator B of the present invention is by two kinds of plates (X plate and Y plate) mutual alternately laminated composition.

Form vapor chamber between X plate and the Y plate, steam is emitted heat here and is condensed into water with fixed attention.

Form between Y plate and the X plate and concentrate sap cavity, because plate-type evaporator integral body is immersed in the concentrate of evaporation tank C, concentrate enters between Y plate and X plate, and is gone out indirect steam by vapor chamber by the heat heating evaporation that plate transmits, and itself is concentrated.

The plate edge is provided with sealing strip F and back-up block G.Sealing strip F assurance vapor chamber and concentrated sap cavity are not connected; The gap of back-up block G guarantees steam, coagulates the unimpeded mobile of water or concentrate.

The course of work of the present invention is as follows:

1. solution to be concentrated feed process: solution to be concentrated enters preheating in above each fresh water preheater of imitating and the dense water preheater successively by the most last effect (lowest temperature effect), through preheating, enters first at last and imitates evaporation tank.

2. concentrate flow process: enter first and imitate through the solution to be concentrated of preheating and imitate in the plate-type evaporator of evaporation tank by external heat source steam (or hot water) evaporation first, concentrate, become concentrate and indirect steam, be concentrated liquid and enter two effect evaporation tanks by pipeline, dense water preheater.All go up one and imitate lowly because two imitate the evaporation tank temperature, pressures, imitate two therefore that shwoot goes out the fraction steam in the evaporation tanks, itself temperature is reduced to two and is imitated evaporating temperatures, imitates in the evaporation tanks two simultaneously and is imitated the plate-type evaporator evaporation and concentration by two.The two thermal source steam of imitating plate-type evaporator are imitated the indirect steam that evaporates from first.The rest may be inferred for each effect later on, until the last effect.Concentrate is concentrated by stepped evaporation and is extracted out through pump by the most last effect.

3. steam and current journey with fixed attention: external heat steam enters first and imitates the plate-type evaporator vapor chamber, emits heat, and the first concentrate heating evaporation of imitating evaporation tank is gone out indirect steam, and itself condenses into water; Emit the part heat through the fresh water preheater of this effect again, enter next and imitate the fresh water preheater.

The vapor chamber that the indirect steam that is evaporated by the first effect plate-type evaporator enters the second effect plate-type evaporator, emit heat, the second concentrate heating evaporation of imitating in the evaporation tank is gone out indirect steam, itself condense into coagulating of the water and first effect and enter next effect fresh water preheater after water converges.Below each imitates that the rest may be inferred, until the last effect.All coagulate water and all extract out, as desalination water by condensate pump.

The present invention has overcome many defectives that original tubular type multiple-effect evaporation desalination concentrates, and is the ideal style that a new generation's evaporation desalination concentrates.

Claims

1. multiple-effect evaporation enrichment facility, comprise multi-effect evaporator, dense water preheater and fresh water preheater, the concentrated solution outlet of adjacent every single-effect evaporator and inlet and coagulate between water out and the inlet respectively with pipeline connect a dense water preheater and a fresh water preheater, the steam (vapor) outlet of the evaporimeter of a last effect is connected with pipeline with the steam inlet of the evaporimeter of adjacent next effect; Concentrate to be evaporated is connected to each the fresh water preheater and dense water preheater of imitating of front successively by temperature the most last minimum effect and carries out preheating, connect the steam inlet that enters the first the highest single-effect evaporator of temperature at last, it is characterized in that: described each single-effect evaporator is made up of one or more groups plate evaporation unit, and this plate evaporation unit is immersed in the evaporation tank by one or more plate-type evaporators to be formed; Concentrate in the evaporation tank of every group of plate evaporation unit is imitated on the same group by pipeline and next, and evaporation element links to each other; After the concentrate that also every effect how can be organized evaporation element compiles, be connected to next effect; The steam inlet of described plate-type evaporator and concentrate inlet are located at the edge side of plate.

2. one kind is carried out the method that multiple-effect evaporation desalination concentrates with the described device of claim 1, comprises preheating, evaporation, condensing steps in each is imitated, and it is characterized in that:

Concentrated liquid to be evaporated in the described preheating step is imitated the concentrate inlet that is preheated to first single-effect evaporator by multistage dense water preheater, fresh water preheater step by step by art;

Concentrated liquid to be evaporated in the described evaporation step is concentrated by stepped evaporation until the most last effect in first effect, second effect after the preheating successively, and the concentrate of finishing is extracted out from the most last effect; Every effect condensed water is imitated to enter step by step from first and is extracted out from the most last effect as desalination water after next effect is compiled;